Chemistry Commons^™

Conjugate Additions And Transposition Of The Allylic Alcohols Of Enol Ethers Of 1, 2-Cyclohexanedione., Barnabas Otoo

Electronic Theses and Dissertations

A variety of protected enolic forms of 1, 2-cyclohexanedione was prepared as substrates for conjugate addition studies using organocopper reagents. The sequence involved the enol ether preparation via the enolate, alkylation with an organometalic reagent, and oxidative rearrangement with pyridinium chlorochromate followed by the conjugate addition reactions. Protection of 1, 2-cyclohexanedione was achieved by reacting with chloro tert-butyldimethyl silane and subjected to alkylation. Steric problems were encountered and so an alternative protective group the methoxymethyl acetal was prepared and studied. Alkylation of these derivatives was successful; however, the oxidation was problematic and although evidence for rearrangement was observed in one …

Preparation And Studies Of Fluorescent Carbon Nanomaterials, Xin Wang

All Dissertations

There have been rapid advances in the development and applications of semiconductor quantum dots (QDs) represented by CdSe/ZnS. However, a serious limitation of these QDs is the necessary use of toxic heavy metals. Fluorescent 'carbon dots' (surface passivated carbon nanoparticles) are developed as alternative to classical semiconductor QDs.
The carbon dots could be made to be highly fluorescence, with emission quantum yields close to 60%. Their optical properties resemble bandgap transitions found in nanoscale semiconductors, suggesting that carbon particles at the nanoscale acquire essentially semiconductor-like characteristics.
The fluorescence in carbon dots could be quenched efficiently by electron acceptor or donor …

The Removal Of Wood Components From Hardwood By Hot Water, Rory Jara

Electronic Theses and Dissertations

Hot-water extraction of hemicelluloses from wood is a promising technology in the integrated biorefmery concept. A particular case is where the pulp industry makes co-products such as ethanol and acetic acid besides pulp thereby maximizing the value of biomass. Similarly, the oriented strand board (OSB) industry appears to be suitable for this technical approach as it is composed of large centralized facilities. Many studies have been carried out on the kinetics and mechanism of hot-water extraction of lignocellulosics. However, most of these studies were performed in batch reactors which are not best suited to determine intrinsic kinetics of hemicellulose dissolution …

Design And Regioselective Synthesis Of Two And Three-Pronged C60 Fullerene Derivatives And Their Applications In Molecular Electronics, Angy Ortiz-Hernandez

All Dissertations

Since the introduction of semiconductors in the second half of the 20th century, advancements in electronics and technology have been tremendous. In particular, the rapid development of silicon-based computer chip technology and miniaturization of electronic components has been tremendous. Since silicon-based materials have a limit in terms of size, scientists proposed that individual molecules could behave as single electronic components for high degree of miniaturization.
Given that the molecules of interest must have dimensions on the nanometer scale, be able to bind to the electrode surface and have electron donor-acceptor properties, C₆₀ fullerene has been a prime candidate for …

Novel Neomycin Conjugates For Multi-Recognition Of Nucleic Acids, Albert Willis

All Dissertations

Neomycin is an aminoglycoside antibiotic known for its high affinity for RNA duplex structures. Recent developments from our labs have indicated that aminoglycoside binding is not limited to RNA, but to nucleic acids that, like RNA, adopt conformations similar to A-form. Our group sought to further expand the utility of aminoglycoside binding to B-DNA structures by conjugating neomycin, an aminoglycoside antibiotic, with the B-DNA minor groove binding ligand Hoechst 33258. Envisioning a dual groove-binding mode, we have extended the potential recognition process to include a third, intercalative moiety. Furthermore, we observe remarkable recognition of such conjugates with RNA duplex. Spectroscopic …

Part I: Synthesis Of Pyrrolo[1,2-A]Indoles Part Ii: Studies Towards Arboflorine, Michael B. Johansen

Electronic Thesis and Dissertation Repository

Part one of this thesis focuses on the synthesis of pyrrolo[1,2-a]indoles from nitrones and 1,1-cyclopropanediesters, by way of tetrahydro-1,2-oxazines. A five step synthetic sequence through tetrahydro-1,2-oxazine synthesis, intramolecular Heck reaction, Krapcho dealkoxycarbonylation, reductive N-O bond cleavage, and acid catalyzed transannular alcohol displacement, is developed to access the desired pyrrolo[1,2-a]indoles. Part two of this thesis details the functionalization of indoles by installation of a malonate moiety, by means of copper catalyzed carbenoid reactivity. A wide range of malonyl indoles with varying substitution patterns is shown to be accessible through the developed method. The final chapter focuses on the application of this …

Characterization Of Metastasis-Associated Cell Surface Glycoproteins In Prostate Cancer, Lifang Yang

Theses and Dissertations in Biomedical Sciences

Prostate cancer (PCa) is a major health problem in males in the United States. Its lethality is mostly attributed to the primary tumor metastasizing to distant sites that are highly resistant to conventional therapies. Serum Prostate Specific Antigen (PSA) is the only protein biomarker used in clinic for prediction of prostate cancer recurrence following local therapies. Nonetheless, PSA lacks the ability to predict the behavior of an individual tumor in an individual patient. Therefore, development of reliable biomarkers for detection of metastatic potential in primary tumors, as well as discovery of new therapeutic targets, is in a great need for …

Boron And Titanium(Iv) Halide Mediated Reactions, Michael Patrick Quinn

Doctoral Dissertations

This dissertation summarizes research efforts focused on the use of boron and transition metal halides to form new carbon-carbon and carbon-halide bonds. The boron halide mediated alkyne-aldehyde coupling reaction to generate 1,3,5-triaryl-1,5-dihalo-1,4-dienes was reinvestigated in an attempt to explain the stereochemistry observed during changing of both the mode of addition and the reaction temperature. Either (Z,Z)-1,4-dienes or (Z,E)-1,4-dienes can be the predominant product depending on reaction conditions used. This mechanistic investigation also led to the discovery of several novel reactions. These include the stereoselective preparation of (Z)-3-chloroallylic ethers from the reaction of alkenylboron dichlorides with aryl aldehydes in the presence …

Vibrational Spectroscopic Study Of The 1,3,5,7-Cyclooctatetraene At High Static Pressures, Edward Romano

UNLV Theses, Dissertations, Professional Papers, and Capstones

1,3,5,7-cyclooctatetraene (COT) is a single-ringed hydrocarbon that has not been studied extensively under high static pressures. It was the intent of this study to reveal its high-pressure behavior through its vibrational spectra. To this end, its infrared spectra as a function of pressure were collected at the National Synchrotron Light Source (NSLS) U2A beamline, as well as its Raman spectra over pressure using a micro-Raman spectrometer.

The spectra show the typical stiffening of force constants with increasing pressure for most peaks, particularly those which would theoretically exhibit a mode-softening behavior under hypotheses of molecular planarization and aromatization. Additionally, the data …

Synthesis And Characterization Of Photoactive Amorphous Molecular And Polymeric Pyridinium Materials, Alexi Kamenov Nedeltchev

UNLV Theses, Dissertations, Professional Papers, and Capstones

Pyridinium materials both molecular and polymeric are interesting class of multifunctional electrolytes and polyelectrolytes, which exhibit liquid-crystalline and light-emitting properties. Moreover, their properties could be easily tuned simply by modifying the chemical structures of counterions.

In this dissertation, we described the preparation and analysis of new ionic molecular materials based on bis(pyridinium salt)s and a new class of poly(pyridinium salt)s with various heterocyclic moieties in their backbones with various organic counterions. They were prepared by either ring-transmutation reaction or by metathesis reaction. Their chemical structures were confirmed by FTIR, 1H and 13C NMR spectroscopy and elemental analysis. They had excellent …

Library Synthesis Of Anticancer And Antibacterial Agents Via Azide Chemistry, Jianjun Zhang

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Various anticancer and antibacterial agents have been synthesized via azide chemistry by taking advantage of carbohydrate. Starting from the synthesis of 14 glycosyl azides, a library of carbohydrate-oxazolidinone conjugates and a library of carbohydrate-cyclopamine conjugates with biological interests were synthesized based on a highly efficient "click reaction" assisted by sonication. Some of the conjugates have improved solubility and enhanced anticancer activity.

A library of neomycin B derivatives with various modifications at the 5" position has been synthesized. Two leads exhibit prominent activity against both methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE). Antibacterial activities were measured when combined with other …

Bacillus Cereus And Bacillus Anthracis Germination Kinetics: A Michaelis-Menten Approach, Helen Luu

UNLV Theses, Dissertations, Professional Papers, and Capstones

Bacillus species are rod-shaped, gram-positive bacteria that are capable of producing endospores. In this dormant stage, the endospores can persist in hostile physical and chemical environments. Once conditions become favorable, the spores germinate into actively dividing cells, vegetative cells. Germination is a crucial step for the pathogenicity of the Bacilli in affecting a host organism.

Our study applies mathematical approaches to spore germination to determine whether the binding of one germinant will affect the binding of another germinant. We pursued this approach with two different species, B. cereus and B. anthracis, both pathogenic organisms. B. cereus is a widely known …

Developing A Biosensor For The Detection Of Bacteria: A Comparison Of Methods For Isolating Bacteria-Specific Antibodies, Scott Allen Walper

Dissertations

The antigen-antibody interaction is known to be a high affinity and highly specific interaction that can readily be used for the detection and identification of biological and chemical agents. These studies were conducted to develop an efficient and cost-effective method of obtaining bacteria-specific antibody molecules for integration into a fielddeployable biosensor. Antigen-binding molecules were obtained both as full-length IgG molecules from a hybridoma cell line and as recombinant single-chain Fv (scFv) antibodies isolated from naïve and immunize libraries. Monoclonal and recombinant antibody systems were compared on the effectiveness of producing new, target-specific molecules; the efficiency of production and purification of …

The In-Situ Removal Of Menthofuran From Peppermint Oil And Subsequent Reactions Of The Solid-Supported Adduct, Robert Joseph Justice Ii

Dissertations

Menthofuran is an aromatic heterocyclic compound found naturally in the essential oil of Mentha piperita L. or peppermint. Natural peppermint oil may contain between approximately 2 to 8% menthofuran.

Peppermint oil is a complex mixture of over 350 identified chemical compounds; market demands dictate the extent of processing the oil undergoes prior to being introduced into consumer goods. Menthofuran has long been known to readily autoxidize, either alone or within the peppermint oil matrix, leading to a discolored oil with negative organoleptic consequences that adversely affects its commercial viability. Therefore, a facile method for selective removal of menthofuran was developed …

The Development Of An Effective Water-Soluble Receptor For Pyrene Derivative Dyes, Ashley Longstreet

Undergraduate Theses and Capstone Projects

A receptor with enhanced water solubility was synthesized from an existing receptor to be used as a pyranine fluorescence quencher in endovesiculation detection assays. The existing receptor consisted of a cyclen core with four protruding arms containing an aryl nitro group at each end. Its poor water solubility limited the accuracy and precision of the endovesiculation assay because the low concentration of receptor did not match the concentration of pyranine. To increase the water solubility, ethoxy groups were attached to the ends of each arm by first selectively reducing the nitro group to an amine with NaBHU4, H2, and a …

Calculation Of Collisional Cross Sections For The ²P3/2 > ²P1/2 Transition In Alkali-Noble Gas Systems, Samuel D. Butler

Theses and Dissertations

Collisional cross sections were calculated as a function of energy for two coupled one dimensional, spherically symmetric potentials. The Split Operator Method was used to propagate an initial Moller state, chosen to be a Gaussian in the asymptotic limit, through a potential. The correlation between the wave packet and Moller final state was calculated at each time step. Using the Channel Packet Method, the correlation function was used to obtain scattering matrix elements. From scattering matrix elements for several different effective potential values and using the Method of Partial Waves, the collisional cross section is calculated for the transition from …

Development Of Novel Ahr Antagonists, Hyosung Lee

University of Kentucky Doctoral Dissertations

Aryl hydrocarbon receptor (AHR) is a sensor protein, activated by aromatic chemical species for transcriptionally regulating xenobiotic metabolizing enzymes. AHR is also known to be involved in a variety of pathogenesis such as cancer, diabetes mellitus, cirrhosis, asthma, etc. The AHR signaling induced by xenobiotics has been intensively studied whereas its physiological role in the absence of xenobiotics is poorly understood. Despite a number of ligands of AHR have been reported thus far, further applications are still hampered by the lack of specificity and/or the partially agonistic activity. Thus, a pure AHR antagonist is needed for deciphering the AHR cryptic …

Solid Supported Synthesis Of Secondary Amines Via Staudinger And Microwave Aza-Wittig Reactions, Kyle Thomas Holsinger

Undergraduate Honors Thesis Collection

Amine bond formation is a major topic in organic chemistry and is widely applied to the formation of medicinal compounds. Current studies have analyzed the benefits of microwave irradiation and solid supported reagents in order to improve reaction conditions and both synthetic and environmental costs. In the synthesis of amines, we investigate the combined use of microwave irradiation and solid supported reagents in the aza-Wittig and reductive amination reaction.

Dechalcogenative Allylic Selenosulfide And Disulfide Rearrangements For Cysteine Modification And Glycoligation, Venkataraman Subramanian

Wayne State University Dissertations

This thesis describes investigations directed at the development of methods for the selenosulfide and disulfide rearrangements for the permanent functionalization of thiols, and in particular of cysteine and carbohydrate based thiols. Emphasis is placed on the newly invented silver mediated allylic desulfurative rearrangement for the primary modification of thiols and the synthesis of complex oligosaccharide mimics.

Chapter one introduces the concept of chemoselective ligations for the modification of macromolecules like carbohydrates and proteins. It overviews the native and non-native ligation techniques for their modification of such entities with a attention focusing on thiol based ligation techniques. The later part of …

Synthesis Of Functionalized Gpi Anchors And Related Glycoconjugates, Benjamin M. Swarts

Wayne State University Dissertations

This dissertation is divided into two chapters describing the background, significance, and synthesis of GPI anchors and GPI-anchored molecules. GPI anchors are a class of complex glycolipids with the primary purpose of attaching cell surface proteins/glycoproteins to the cell membrane. The first chapter is focused on the synthesis of functionalized GPI anchors, and begins with an introductory look at the discovery, structure, biosynthesis, and biological functions of GPIs. Then, after surveying progress and achievements in GPI synthesis, including discussion about current strategic shortcomings in the field that prevent the chemical synthesis of various GPI derivatives, our approach to accessing uniquely …

I-Kinetic And Mechanistic Investigations Of Amino Acid Substrates Reactivities With Ferryl Species, Ahmed Ibrahim Youssef Abouelatta

Wayne State University Dissertations

ABSTRACT

I-KINETIC AND MECHANISTIC INVESTIGATIONS OF AMINO ACID SUBSTRATES REACTIVITIES WITH FERRYL SPECIES

II-SYNTHESIS AND CHARACTERIZATION OF DERIVATIVES OF THE BN-TPEN LIGAND AND THEIR METAL COMPLEXES

by

AHMED IBRAHIM YOUSSEF ABOUELATTA

MAY 2011

Advisor: Dr. Jeremy Jacob Kodanko

Major: Chemistry (Organic)

Degree: Doctor of philosophy

The reactivity of tryptophan, methionine, aspartic acid, glutamic acid, histidine and hydrochloride salt of lysine amino acid substrates with the N4Py ferryl species was studied by UV-vis spectroscopy and product characterization. Based on kinetic isotope effect studies and product analysis, an ET-PT mechanism was proposed for the reaction of tryptophan substrate with N4Py ferryl and …

Novel Photochemical Methodologies For Diversity Oriented Synthesis And Screening Of Combinatorial Libraries, Roman Askatovich Valiulin

Electronic Theses and Dissertations

The main goal of this project was to develop an efficient methodology allowing rapid access to structurally diverse scaffolds decorated with various functional groups.

Initially, we discovered and subsequently developed an experimentally straightforward, high-yielding photoinduced conversion of readily accessible diverse starting materials into polycyclic aldehydes and their (hemi)acetals decorated by various pendants. The two step sequence, involving the Diels-Alder addition of heterocyclic chalcones and other benzoyl ethylenes to a variety of dienes, followed by the Paternò-Büchi reaction, was described as an alkene-carbonyl oxametathesis. This methodology offers a rapid increase in molecular complexity and diversity of the target scaffolds.

To develop …

Oxidation Of Dibenzothiophene To Dibenzothiophene Using Metal Nanoparticles Supported On Silica, Karina Castillo

Open Access Theses & Dissertations

Silica and nanoparticles of Pt, Au, and Ag supported on silica were tested for the ability to oxidize dibenzothiophene (DBT) to sulfone. High performance liquid chromatography was used to study the removal of DBT from solution. In addition, X- ray diffraction, infrared spectroscopy and Raman Spectroscopy were used to characterize the product of the oxidation reaction. Further studies involved the use X-ray absorption spectroscopy to characterize the nanoparticle catalysts before and after the oxidation reaction.

To better understand the reaction, silica was synthesized at different pHs using three different acids. The acids used to synthesize the silica were HCl, HNO3, …

A New Photochemical Method For The Preparation Of Amino Acid-α-Phenylthioesters And Peptide-α-Phenylthioesters, Tyrone Hogenauer

Open Access Theses & Dissertations

We describe the development of a novel resin with a photoreactive N-acylnitroindoline linker that allows for the synthesis of amino acid- (in solution) or peptide-α-thioesters using standard Fmoc/t-Bu standard solid phase peptide synthesis (SPPS). Recent advances have shown that the yields of this thioesterification reaction have dramatically increased due to a simple change in the order of addition of reagents. Upon illumination with UV-light, in the presence of N-hydroxybenzotriazole (HOBt), the amino acid- or peptide-α-OBt ester is generated by direct photo-release from the nitroindoline linker with minimal epimerization, followed by reaction with thiophenol in the dark to produce amino acid-α-phenylthioesters …

Conversion Of Racemic Ibuprofen To (S)-Ibuprofen, David Chavez-Flores

Open Access Theses & Dissertations

Ibuprofen is a common Non-Steroidal Anti-Inflammatory Drug (NSAID) sold as a racemic or equal mixture of (R) and (S) mirror-image enantiomers. Without patent protection, ibuprofen is an orphan drug even though one enantiomer, (S)-ibuprofen, provides relief three times faster than its racemic mixture with fewer side effects. The goal of this research was to develop a facile, environmentally benign (no waste of ibuprofen or catalysts), and inexpensive process to convert a commercially available racemic mixture of ibuprofen to the therapeutically active (S)-ibuprofen.

After many attempts, the most successful conversion of racemic ibuprofen to (S)-ibuprofen was the in situ racemization and …

Approaches Towards The Synthesis Of Bradyoxetin, Vanildo Martins Lima Braga

Electronic Theses and Dissertations

Quorum sensing bacteria produce and release chemical signal molecules (like N-acyl homoserine lactones, AHL) that increase in concentration as a function of cell density. The responses cover a large spectrum of process such as the virulence in Staphylococcus aureus, competence for DNA-uptake in Bacillus subtilis and Streptococcus pneumoniae, sporulation in Bacillus subtilis, conjugal plasmid transfer in Enterococcus faecalis, and bacteriocin production in lactic acid bacteria. The collapse of (AHL) signaling system in bacteria represents an attractive therapeutic approach towards the development of new antibiotics. Recently, a new extracellular modulator was isolated from a symbiotic bacterium (Bradyrhizobium japonicum) that nodulates soybean. …

Transition Metal-Mediated Higher-Order Cycloaddition Reactions: Application To The Total Synthesis Of Complex Natural Products, Bilal Abou Aleiwi

Wayne State University Dissertations

ABSTRACT

TRANSITION METAL-MEDIATED HIGHER-ORDER CYCLOADDITION REACTIONS: APPLICATION TO THE TOTAL SYNTHESIS OF COMPLEX NATURAL PRODUCTS

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BILAL ABOU ALEIWI

October 2010

Advisor: Dr. James H. Rigby

Major: Chemistry (Organic)

Degree: Doctor of Philosophy

Chromium (0)-mediated [6ð + 2ð] and [6ð + 2ð + 2ð] cycloaddition reactions between cyclic trienes and alkynes is reported. The development, investigation and the application of these reactions in the total synthesis of complex ring systems and natural products is described. Two natural products, namely, ∆ 9(12) -Capnellene and Echinopines A and B were targeted.

An investigation led to the successful development of a methodology to …

A Bioarchaeological Study Of A Prehistoric Michigan Population: Fraaer-Tyra Site (20sa9), Allison June Muhammad

Wayne State University Dissertations

ABSTRACT

The Saginaw Valley Region has been the focus of Michigan archaeology for many decades. The Late Woodland period of the Saginaw Valley has been characterized as an area that prehistoric people abandoned as a permanent resident, but exploited seasonally during times of scarcity. Furthermore, the valley's resources were exploited by a diverse group of prehistoric peoples, both native to Michigan and those Mississippian `intruders' (Halsey 1976; Holman and Brashler 1999; Norder et al. 2003; Stothers 1999). Though previous studies of the Frazer-Tyra site (20SA9) have included ceramic and lithic analysis (Andrews 1995; Halsey 1976) and a study of mortuary …

I. Microwave-Influenced Diversity-Oriented Synthesis Of Biologically Relevant Small & Natural-Product-Like Molecules Via Multicomponent Coupling Reactions Ii. Synthetic Studies Toward The Total Synthesis Of The Repeating Tetrasaccharide Unit Of Zwitterionic Polysaccharide Ps A1, Soumava Santra

Wayne State University Dissertations

Microwave-influenced diversity-oriented synthesis of biologically relevant small and natural-product-like molecules via multicomponent coupling reactions (MCCRs) have been investigated. Cheap, readily available starting materials in conjunction of microwave irradiation and employment of environmentally benign solvent (e.g. water) provided a common platform that allowed to access a wide array of structurally and skeletally diverse molecules. The investigation allowed us to establish a new paradigm of diversity-activity relationships (DARs) by tuning reacting components of the MCCRs and proved that in contrary to the conventional use of microwave as a rate accelerating tool, it can be used to influence reactivity of molecules. The method …

Development And Applications Of Thioacids In Peptide Chemistry And Exploration Of Methods Toward The Stereochemical Elucidation And Synthesis Of Virgineone, Kasinath Sana

Wayne State University Dissertations

ABSTRACT

DEVELOPMENT AND APPLICATIONS OF THIOACIDS IN PEPTIDE CHEMISTRY AND EXPLORATION OF METHODS TOWARD THE STEREOCHEMICAL ELUCIDATION AND SYNTHESIS OF VIRGINEONE

by

KASINATH SANA

December 2010

Advisor: David Crich

Major: Chemistry

Degree: Doctor of Philosophy

This dissertation describes investigations toward the development of methods for the synthesis of peptidyl thioacids and thioesters, with particular emphasis on applications in peptide chemistry, and the exploration of methods toward the assignment of the relative and absolute configuration of virgineone and its total synthesis.

The first part of chapter one introduces the general characteristics and reactivity of thioacids, and describes their potential for application …